This invention relates to a silver halide photo-sensitive material. More particularly, the present invention relates to a silver halide color photographic sensitive material in which non-diffusion couplers capable of forming non-diffusion dyes are incorporated into a silver halide emulsion layer. The emulsion layer is processed by a color developer containing aromatic primary amine color developing agents and is subjected to photographic processing with a processing solution having a bleaching capacity, thereby forming color images on color photographs.
There are known, various photographic additives that are slightly soluble in water. Typical photographic additives include oil-soluble couplers, antioxidizing agents (alkyl hydroquinones, alkyl phenols, chromans, coumarones, etc.) used for inhibiting fading, color fog or color mixing, hardening agents, oil-soluble filter dyes, oil-soluble ultraviolet light absorbing agents, oil-soluble fluorescent whitening agents, DIR compounds (DIR hydroquinones, colorless DIR couplers, etc.), developers, dye developing agents, DDR redox compounds and DDR couplers. Such photographic additives are dissolved in an adequate oil forming agent, i.e., a high-boiling organic solvent. Commonly used as the high-boiling organic solvent are phthalic acid ester compounds and phosphoric acid ester compounds. The solution of the dissolved additives is included in a hydrophilic organic colloidal layer such that the additives are dispersed in an aqueous solution of hydrophilic organic colloid such as gelatin in the presence of surfactants. The colloidal layer may be a photo-sensitive emulsion layer, a filtering layer, a backing layer, an antihalation layer, an interlayer or a protective layer.
The phthalic ester compounds and the phosphoric ester compounds that serve as the high-boiling organic solvents have been used widely in the photographic field. This is because these compounds are available at low cost, are superior in affinity to colloid such as gelatin and are favorable for dispersing the couplers. In addition, the compounds have a good effect on stability and the hue of formed color images and are chemically stable in the photo-sensitive materials.
However, these well known high-boiling organic solvents (including the phthalic ester compounds and the phosphoric ester compounds) are still insufficient for the more recent photo-sensitive materials that are required to have high performance especially in view of the effects of inhibiting staining and fading of the color images due to light, heat and moisture.
As mentioned above, various requirements have been imposed on the high-boiling organic solvents used for recent photo-sensitive materials. Typical requirements for the high-boiling organic solvents are as follows. They should be readily available or manufactured at low cost and have superior solubility and dispersion stability in photographic additives. The exertion of no adverse effect on developing and photographic properties is also required. Other requirements are involved in safety considerations and the effects on the environment. In addition, the solvents should be excellent in chemical stability and be good for inhibiting the fading of the color images in the case of silver halide color photo-sensitive materials.
In the color photo-sensitive materials, the dyes formed by reaction of the coupler with the developing agent, especially pyrazoloazole magenta dyes and pyrroloazole cyan dyes, are more easily associated with each other in a film. As the absorption band maximum of the aggregates differs from that of dye monomers, excessively large absorption by the aggregates is inadequate due to considerations of color reproduction.
With this respect, a color photo-sensitive material capable of reproducing favorable or desired colors could be provided at a lower manufacturing cost if it would be possible to adjust the absorption band maxima of the dyes by means of shifting the maxima to a shorter or longer wavelengths using additives or the like contained in the same layer as the dyes rather than altering the structure of the dye.
As for these problems, it has been found that some high-boiling organic solvents that could be used as a dispersing medium for the dye-forming non-diffusion couplers have the effect of shifting the absorption maxima of yellow, magenta and cyan dyes towards shorter or longer wavelengths. It has also been found that other high-boiling organic solvents of the type described have the effect of restricting or enhancing the association of the dyes and serve to shift the absorption band. Concern about the presence of such solvents has increased.
For example, JP-A-63-301941 (the term "JP-A" as used herein means an "unexamined" published Japanese patent application) discloses phosphine oxide, phosphinate and phosphonate having the above mentioned effects. However, it is usually difficult with these compounds to provide a sufficient level of the dye hue along with the improved dispersion stability and solubility of the materials required when they are used as the dispersing media. As a result, the color forming properties of the dye-forming non-diffusion couplers tends to decline. In addition, the above mentioned compounds tend to enhance the fading of the dye obtained from the coupler because of, for example, heat, moisture and light when they are incorporated into the same layer as the dye-forming non-diffusion couplers.